Tuesday, July 22, 2008

List of computer viruses

To aid the fight against viruses and other malware many security advisory organizations and developers of anti-virus software compile and publish lists of viruses. A single comprehensive list would make sense, but no definitive list currently exists.

Contents

One fundamental fact that makes the compilation of a unified list of viruses difficult is naming. When a new virus appears, the rush begins to identify and understand it as well as develop appropriate counter-measures to stop its propagation. Along the way, a name is attached to the virus. As the developers of anti-virus software compete partly based on how quickly they react to the new threat, they usually study and name the viruses independently. By the time the virus is identified, many names denote the same virus, and these different names have been used enough to stay around.

Another source of ambiguity in names is that sometimes a virus initially identified as a completely new virus is found to be a variation of an earlier known virus, in which cases, it is often renamed. For example, the second variation of the Sobig worm was initially called "Palyh" but later renamed "Sobig.b" . Again, depending on how quickly this happens, the old name may persist.

In terms of scope, there are two major variants: the list of "in-the-wild" viruses, which list viruses in active circulation, and lists of all known viruses, which also contain viruses believed not be in active circulation (also called "zoo viruses"). The sizes are vastly different, in-the-wild lists contain a few hundred viruses but full lists contain tens of thousands.